Germany invaded poland in 1939. They fast moving armies encircled polish forces, but the blitzkrig idea never really took hold; artillery and in fantry forces acted in time-honoured fashion to crush these pockets.
The Invasion of Poland, also known as the September Campaign or 1939 Defensive war.
the polish Army had approximately a million soldiers, but less than 1/2 of them were mobilized by 1 september. The polish military had fewer armored forces than the Germans, and these units, dispersed within the infantry, were unable to effectively engage the enemy.